Framing constructions for wall openings, such as to accommodate doors, usually have some form of weatherstripping or other insulating means particularly when the door opens to the outside environment. Typically, residential door frames have a wood jamb which has its inherent insulating characteristics. However, metal door jambs, such as of steel, often are used for more heavy duty applications. The use of steel framing components sacrifices the insulating characteristics of wood. Therefore, steel jambs or framing assemblies have been made of at least two pieces with an insulating barrier to solve the insulation problem inherent in the use of metal materials.
The insulating problem actually is two-fold. First, a weatherstrip is used for engagement by the door itself. Usually, the weatherstrip is compressible when the door closes to seal the door opening against air movement. Second, a thermal break must be used between the two pieces of the metal jamb to prevent conduction of heat from the interior of a building through the jamb to the exterior.
An example of a thermal break for a steel door frame is shown in U.S. Pat. No. 4,594,831 to Winyard, dated June 17, 1986. That patent shows a thermal break of rigid, low.-thermoconductive material, such as vinyl or the like, comprising a multi-faceted flanged component for receiving the flanges of two metal frame members, one of the members forming the soffit and stop of the door jamb and the other member forming the rabbet of the door jamb. Such a multi-faceted construction is widely used but rather complicated to assemble, replace or maintain. In fact, Winyard's preferred construction is made into pieces just to allow for replacement of the weatherproofing strip portion of the thermal break as it wears out or is damaged in use.
This invention is directed to solving such problems with a very simple door frame assembly incorporating a unitary weatherstrip with an integral thermal break.